In digital cameras, conventionally, an image sensed by using an image sensing element is converted into image data and recorded in the internal memory of the digital camera or on a recording medium such as a detachable memory card. Many of such digital cameras have display devices such as a liquid crystal monitor, and obtained image data can be displayed on the display device so that the user can confirm the sensed image.
A display/playback device such as a liquid crystal monitor used in a digital camera is small and simple and therefore cannot display all pixels of the sensed image. To display an image, the number of pixels is reduced by, e.g., thinning them. Although the composition of an object can be confirmed even on such a small and simple display/playback device, precise conditions such as the focus state of an image cannot be confirmed. For this purpose, a digital camera having a function of magnifying and playing back part of an image has been proposed.
The magnifying playback/display function will be described below with reference to the accompanying drawings.
The magnifying playback/display function causes a playback image selector to select an image to be played back and magnifies and plays back the selected image. In a sensed image shown in FIG. 11A, the central region of the screen is magnified first by the magnifying playback/display function. The magnified portion for the image shown in FIG. 11A corresponds to, e.g., the rectangular frame portion at the center in FIG. 12A. The frame size changes depending on the magnification ratio. More specifically, when the magnification ratio is high, the frame size decreases to magnify a smaller region. When the magnification ratio is low, the frame becomes large to magnify a wider region. FIG. 13A shows only the portion inside the rectangular frame in FIG. 12A. This image is magnified in the magnifying playback/display mode and displayed on an external display device of the digital camera.
To magnify and confirm another portion of the image, the magnifying playback region is changed by using a position selection unit, thereby obtaining a necessary image. An example will be described below, in which the photographer wants to confirm the shot state of the head part of a person as an object in the image shown in FIG. 11A and changes the magnified region.
FIG. 13B shows an image which is obtained when the magnified region is moved upward by several steps from the state shown in FIG. 13A in order to confirm the upper portion of the current image. The magnified region corresponding to the image shown in FIG. 13B in the image shown in FIG. 11A is indicated by a rectangular frame in FIG. 12B. Since the left hand of the person can be recognized in FIG. 13B, the user can know that the head part of the object is present on the left side of the part shown in FIG. 13B. FIG. 13C shows an image which is obtained by moving the magnified region to the left from the state shown in FIG. 13B. The magnified region corresponding to the image shown in FIG. 13C in the image shown in FIG. 11A is indicated by a rectangular frame in FIG. 12C. FIG. 13C shows the head part of the person as the object, though the head part is not wholly displayed. FIG. 13D shows an image which is obtained when the magnified region is moved upward from the state shown in FIG. 13C in order to display the entire head part. The magnified region corresponding to the image shown in FIG. 13D in the image shown in FIG. 11A is indicated by a rectangular frame in FIG. 12D. In this way, the magnifying/playback position can be changed to the photographer's desired position. Hence, the image can be confirmed even on the small and simple display/playback device.
However, this method is cumbersome for magnifying and playing back a plurality of images.
To magnify and playing back another image different from the image that is currently being played back, the magnifying playback of the current magnified image is ended, and then, another image is selected by the image selector. After that, the magnifying playback mode must be set to magnify the central portion of the image and move the magnified region to a desired position.
Photographer's desired magnifying playback portions are not always present at the center and tend to concentrate at his/her favorite position. Further, in a series of images taken in a continuous shooting mode, the region to be magnified and confirmed is often present at the same position.
For example, FIG. 11B shows an image that is sensed next to the image shown in FIG. 11A in the continuous shooting mode. When magnifying is done in accordance with the conventional procedures, the image shown in FIG. 14A is displayed first. However, the image shown in FIG. 14B is the photographer's desired magnified image. The rectangular frames shown in FIG. 15 indicate the relationship between FIGS. 14A and 14B in the image shown in FIG. 11B. As is apparent from FIG. 15, the magnified regions shown in FIGS. 13D and 14B in the original images are at the same position. However, to obtain the magnified image shown in FIG. 14B, the same magnified region change operation as that executed in obtaining the image shown in FIG. 13D for the image shown in FIG. 11A must be executed again.
Some digital cameras display a sensed image for a short time right after sensing the image (this function is referred to as “REC review” hereinafter) so that the photographer can confirm the sensed image immediately after sensing. When the image is magnified during the REC review, details of the image can be confirmed even in the REC review mode. However, when a series of photographs are taken by continuous shooting and almost the same regions in the series of images should be magnified and confirmed in the REC review mode, the above operation must be repeated, i.e., a the central region is magnified for each image, and the magnified region must be moved from the central portion to the desired region.
Since this operation is cumbersome, and it requires considerable time to confirm images, the user may lose the next shutter chance.